1. Field of the Invention
The present invention relates to a socket, and more particularly to a socket for a wrench and that can securely hold a head of a fastener to rotate the fastener even when the head has been worn away.
2. Description of Related Art
A socket can be attached to a wrench to hold and to rotate a fastener, such as a bolt or a nut. A conventional socket has a body with a central hole defined in one end of the body. A square hole is defined in the other end of the body to engage with a cubic stub protruding from the wrench, such that the socket can rotate with the wrench by means of the engagement between the stub and the hole. The central hole is polygonal and generally has six identical surfaces forming the central hole. The polygonal central hole can engage with a polygonal head of the fastener to drive the fastener to rotate with the socket so as to tighten or loosen the fastener relative to an object.
However, the central hole of the conventional socket cannot securely hold a head of a fastener when the head has been worn away. The worn head cannot be driven to rotate with the conventional socket, and so the use of the conventional socket is limited and is not versatile.
To overcome the shortcomings, the present invention tends to provide a socket to mitigate or obviate the aforementioned problems.
An objective of the invention is to provide a socket for a wrench and that can drive a head of a fastener even when the head has been worn away. The socket has a body with a central hole defined in one end of the body and a connecting device formed on the second end of the body. Multiple first protrusions are formed on the inner surface of the central hole, and each first protrusion has a peak with a first angle. A second protrusion is formed on the inner surface of the central hole between each pair of adjacent first protrusions. Each second protrusion has a peak with a second angle and a recess defined in one side of the second protrusion to make the second angle smaller than the first angle of the peak of the first protrusions. In such an arrangement, the socket can securely hold the head of the fastener with the peaks on the protrusions.
Other objectives and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.